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Advanced Adult ABG and Anion Gap Analyzer

Parameters

Arterial blood-gas values

Enter pH, PaCO₂, and analyzer-reported calculated HCO₃⁻ from the same arterial blood-gas sample. Enter respiratory timing only when it is established clinically.

RequiredAllowed: 6–8

RequiredAllowed: 4–200 mmHg

RequiredAllowed: 1–85 mmol/L

Optional

Contemporaneous chemistry values

Use sodium, chloride, total CO₂, and albumin from one contemporaneous chemistry panel. Chemistry total CO₂ is distinct from analyzer-reported calculated HCO₃⁻ in arterial blood-gas analysis; enter the laboratory's local upper reference for AG without potassium.

RequiredAllowed: 40–205 mmol/L

RequiredAllowed: 50–200 mmol/L

RequiredAllowed: 5–50 mmol/L

RequiredAllowed: 1–80 g/L

RequiredAllowed: 1–30 mmol/L

Clinical context

For adults with one arterial blood-gas sample and one contemporaneous chemistry panel. It combines acid-base pattern assessment with anion gap, albumin correction, and delta ratio when applicable.

What it shows

Arterial blood-gas analysis reports the pH state, acid-base process pattern, and expected physiologic response. The chemistry assessment separately reports uncorrected AG, albumin-corrected AG relative to the entered local reference, and delta ratio when applicable. Low albumin can mask an increased burden of unmeasured anions in the uncorrected gap.

How it works

The Henderson–Hasselbalch relationship checks consistency; HCO₃⁻ reflects the metabolic component and PaCO₂ the respiratory component. Expected-response equations can identify a possible second process. Use sodium, chloride, total CO₂, and albumin from one contemporaneous chemistry panel. Chemistry total CO₂ is measured separately and is not interchangeable with analyzer-reported calculated HCO₃⁻ from arterial blood-gas analysis. AG = Na − Cl − total CO₂ (without potassium) Corrected AG = AG + 0.25 × (40 − albumin [g/L]) Delta ratio = (corrected AG − entered upper reference) / (24 − total CO₂) The entered upper reference must come from the local laboratory; the editable default is an equation convention, not a universal normal limit. Delta ratio applies only when corrected AG is above that reference and total CO₂ is below 24 mmol/L.

Use and limits

Enter an acute or chronic pattern only when already established clinically; otherwise leave it not established. One sample cannot prove the course. A non-elevated anion gap does not exclude important unmeasured anions from lactate, ketones, toxic-alcohol metabolites, or retained renal acids. Delta bands are adjunctive and published conventions vary. For adult arterial samples only. This tool does not assess oxygenation, does not establish etiology, and does not recommend treatment; it excludes pediatric, neonatal, pregnancy-specific, venous, and capillary samples. Interpret all outputs with the patient, local methods and intervals, specimen timing and handling, ventilation, medications, renal function, and toxicology.

Use the simpler analysis without chemistry values